Herr Fokker D-VII 4 ch indoor

I'm posting this here 'cause I intend to fly it at indoor meets that I go to -
I've had this kit in the closet for several years and now I think that I can do something with it. I'd like opinions on this project, but here is what I'm thinking of doing:

Firstly, It has overall WS of 24" if go to tips of the ailerons, for roughly 156 square inches. It is a FF rubber kit as many know and I think I can use three micro servos to get rudder, elev., ESC, plus one to operate both ailerons Also will use CF for pushrods and maybe L. gear, maybe a Berg micro stamp rx, Lipos, and motor. The motor, well, thinking of several that I have already - JPS 300, CD rom motor from Aircraft World, Faulhaber DC 1524 (would probably need to get 6.3:1 gearbox), or GWS IPS-A. My goal is NOT to have a screamer, but rather an easy flyer.

I'm planning to use Japanese tissue and clear dope for cover.

Please let me know what you think about 4 channels, and motor and servo choices

Dave

Images

Dave,
This looks like a great build for an indoor plane. If your outrunner/cd-rom motor is the same as a PJS 300,that would be a great motor for this plane, I use this with a 8x4 APC prop for a tame time with my GWS Tigermoth, you could probably wind your own brushless motor from Gobrushless.com and have a lighter motor that is better suited to this plane though... I have not had much luck winding my own so far…The IPS A will work too, but all the props that have worked well for me in the past would probably be way too big for this airframe.

I think you've got a good project going there. I also like the stick and tissue conversions. The Albatross in my avatar is a DPCModel's rubber FF kit, and it also has ailerons, elevator and rudder. 24" is too big for actuators, but the Falcons give very smooth and positive control, and they have enough grunt to work the ailerons quite well. I wanted to use the cable-in-sheath type controls, but they were too big, heavy and graggy for the small servos, so I went to .008" (or maybe .010", I forget) guitar string working in a teflon tube sheath. The teflon tubing was meant for making CA capillary nozzles and came in a 6' coil from the LHS.

I attached pictures of the aileron hook up I used. It has a Cirrus MJ servo since it was easier to hook up. I talked with the folks at Falcon, and now the newer Falcons now come with a third output arm so the geometry will allow easier aileron operation... The yellow showing in the photo is heat-shrink that binds the .020" brass rod follower to the one-piece guitar string pushrod. the second photo shows the wire and sheath at the aileron waiting for installation of the horn.

Hey guys, thanks for all the info which I'm trying to digest now. Fritz, I will take a look at Gobrushless.com. Not sure I want to wind my own right now, but who knows. The ones (CD rom motors) I have from Aircraft World might be right depending on rpms and torque. I will put the kit magnets in one before trying that.

Pete, I'm thinking of tissue colors of black, red and white with clear dope, not too much painting but the colors will be there. I want to look at color schemes some more though. I remember seeing a great book at B&N showing numerous schemes.

Mike that's a great job with the Albatross, I hope I can do half as nice a job as that! I found the Cirrus servos at AeroMicro but where do you get the Falcon servos? Are they as expensive? The guitar string with the CA tube looks like a neat clean way to link the ailerons, but the one wire to the horn pushes and pulls without bending or flexing and is stiff enough?

Hey, you know, Albatross could be in that cook-up going on 'cause Albatross made some of the Fokker D-VII's

The wire is stiff enough. The bay the servo sits in is just 2" or so - just wide enough to squeeze the MJ into. Since the wire is one piece and supported from both sides, there is no problem there. At the aileron end, there is enough flex to work smoothly without bending. See Bob Selman for the Falcon's here is the U.S. The Albatross was what sparked the interest in the DPCModels and got the DCPM Cook-up going, so it is fairly well known of there... Speaking of which, read through the DCPM cook-up thread and near the end there is a discussion of printing tissue in lozenge pattern camoflage. Jared was nice enough to create printable camo patterns... They are too big to upload here, but if you want the zips PM me with an e-mail address and I'll share...

Mike, pm'd you. Think I will probably emulate your set-up for the ailerons if you don't mind. Looks like you have worked out a smooth linkage there. Your Albatros, is it the 18" D-V? I was looking at the D-XI (26") and think I'm going to have to order one of those, looks pretty sweet.

Yes, that is the 18" model. Dave also released the D-XI during the cook-up, and there are some great shots of a couple being built in the thread, and some fine photos in the picture gallery at SFA. I'm sorry that I don't have any more photos of the aileron details for you, but it pretty much just a scaled down Sullivan type system... Have at it!

I've been looking at sub micro, no - what nano servos? I won't say sub-nano servo, that's probably reserved for the future. Somebody tell me what the term is.

Anyways I've been looking at the Wes Technik LS series and the Falcon servos. I could put about 15 Falcon servos on this thing and add only an ounce or less, so I don't think weight will be the issue here. I don't have a good feel for how much torque or output power I need. The Falcon specs are 25+ grams torque and the WT's are 160 to 200 grams linear force. How much do I need for a Fokker D-VII with 24" wing span? I'm shooting for 5 - 6 oz. or 144 - 170 g. less if possible. Does anyone have a good feel for micro power needed per servo for this application? It's kind of expensive to just experiment with.